System and method for non-binding allograft subtalar joint implant

ABSTRACT

Provided is a system and method for providing a non-binding allograft subtalar joint implant for surgical implant into a person&#39;s foot proximate to the ankle. This system for repair includes at least one sterile non-binding allograft subtablar joint implant provided as a pre-formed allograft rod plug “ARP” having a diameter about equal to an average width of a canal between a person&#39;s talus and calcaneus bones, the ARP being resiliently compressible and flexible. When snuggly disposed between the person&#39;s talus and calcaneus bones, the ARP compresses during normal use of the person&#39;s foot and maintains the canal in an anatomically correct alignment and reduces a tendency for abnormal motion between the person&#39;s talus and calcaneus bones. An associated method of use is also provided.

FIELD OF THE INVENTION

The present invention relates generally to systems and methods for amedical procedure involving an implant for the correction of skeletalmisalignment, and more specifically to a non-binding allograft rod plugimplant for the subtalar joint to stabilize relative alignment betweenthe talus and calcaneus bones of the human foot.

BACKGROUND

A fallen arch or flatfoot is a deformity that affects people young andold. It is a skeletal misalignment deformity in which the arches of thefoot collapse resulting in the entire sole of the foot being in completeor nearly complete contact with the ground. As there is a biomechanicalrelationship between the foot and lower leg, problematic issues in theinner workings of the foot structure adversely affect the rest of thebody.

In proper operation the structure of a healthy arch provides an elasticconnection between the hind foot and forefoot which serves to safeguardthe body during weight bearing activities by displacing the impact forcebefore it reaches the leg bones. For persons afflicted with one or bothfeet suffering from a flat foot condition, this elastic absorption ofthe foot is diminished, if not entirely non-existent. Moreover, inaddition to being painful, pathologic flatfeet may cause bunions,hammertoes, heel spurs, arch pain, growing pains, shin splints, kneepain, and back pain.

Of the many bones within the human foot, the flatfoot condition isclearly evidenced by the head of the talus bone being displaced mediallyand distally from the navicular bone, which in turn causes lateralmisalignment throughout the foot as the talus and navicular tend to moveoutward. In addition, there is a change in relative alignment in thesubtalar joint that occurs at the meeting point between the talus boneand the calcaneus bone such that the canal which should naturally occurbetween them is depressed. This canal is commonly referred to as thesinus tarsi.

The subtalar joint has a neutral position where there are neutral forcespassing through the multiple axis and planes that make up and permit thenatural triplanar motion of the joint. When the subtalar joint's relaxedposition is no longer in the intended neutral position, then thetranslation of forces placed on the surrounding joints, ligaments andosseous structures is abnormal. Simply put, the misalignment of thetalus and calcaneus bones further imposes misalignment on other footbones.

It has been discovered that by re-establishing the relative alignmentbetween the talus and calcaneus bones, the overall arch structure of thefoot can be reestablished as well. While this can be demonstrated byphysically manipulating a person's foot, such physical manipulation isimpractical during a normal use of the foot. As such there have beenvarious efforts made to provide implants which operate to physicallyreposition and realign the talus and calcaneus bones.

Various implants have been developed of varying shapes and materials,such as Titanium, stainless steel, silicone, polyethylene and PEEK. Thegoal of such implants is to stabilize the talus and calcaneus bones withrespect to each other without fusing them. While perhaps effective atreestablishing an improved alignment of the talus and calcaneus bonesthe options for implants known to date fall short of trulyreestablishing the triplanar motion and naturally gliding motion of thesubtalar joint.

One such effort is set forth in the prior art reference of Maxwell U.S.Pat. No. 6,168,631 teaching a Subtalar Implant System and Method forInsertion and Removal. Maxwell specifically teaches an implant sized andshaped to fit within the sinus tarsi, and that the implant has exteriorthreads so as to engage the tissues, i.e. bones, of the sinus tarsi.Maxwell also teaches that the implant is preferably made from a titaniumbased alloy as Maxwell asserts that it is an object of the invention notto deform under post operative compressive forces. While perhapseffective in re-establishing spacing between the talus and calcaneusbones, as the Maxwell implant is quite literally screwed in-betweenthem, the screwing nature also binds them and substantially eliminatesthe natural triplanar motion of the subtalar joint. In addition, themetal nature of the Maxwell implant results in the patient experiencinga hard stop—the foot simply does not move in some directions and theresistance to compression can be painful. In addition, over time and asa result of repeated use of the repaired foot, the Maxwell implant mayactually abrade, or cause the surrounding bone tissues to abrade—leadingto shards of foreign or natural material within the subtalar jointfurther causing pain and perhaps requiring surgical extraction of thedebris, and/or the Maxwell implant itself as suggested by the title.

The prior art reference of Lepow U.S. Pat. No. 8,092,547 for a SubtalarImplant Assembly teaches an implant with a core region 16 that istapered between a first end 24 and a second end, the core region 16further having a threaded region 18 formed on and extending outward. Aswith the Maxwell implant, the Lepow implant is screwed into placebetween the talus 38 and calcaneus 40 bones. As such, once again, thisscrewed in nature binds the talus and calcaneus bones and substantiallyeliminates the natural triplanar motion of the subtalar joint. Lepowalso teaches forming the core region from various plastics, metals,metal alloys, glass, ceramics, composite materials such as carbon fiber,bio-absorbable materials, or the like and combinations of metals and/orplastics. Once again the Lepow implant is intended to be a very solidnon-deformable implant. As such, the motion of the foot may beun-natural and perhaps painful for some person's, and once again shardsof natural and foreign materials may develop within the subtalar jointresulting in pain and the need for surgical extraction.

The prior art reference of Graham U.S. Pat. No. 7,033,398 for a SinusTarsi Implant is yet another threaded implant. The Graham implant isspecifically taught to have a first member 106 with an outer surfacegenerally configured in the shape of a right conical frustrum between asecond member 108 and a cylindrical third member 110, the third member110 being sized to fit within the sinus tarsi. Preferably fashionedabout the cylindrical third member 110 is a tissue engagement surfacemore specifically taught as one or more channels 112, which in apreferred embodiment are a continuous thread. Once again, the Grahamimplant is intended to be screwed into place with the one or morechannels 112 of the third member 110 binding with the talus andcalcaneus bones proximate to the sinus tarsi. And again, such bindinglikely eliminates the natural triplanar motion of the subtalar joint.The Graham implant is also taught to be constructed of by a polymerwhich is substantially incompressible and tough, once again potentiallyresulting in an uncomfortable if not painful implant for some person's.And again, the binding nature of the Graham implant may once againresult in shards of foreign or natural material within the subtalarjoint.

Other threaded implant prior art references exist as well, such as PechU.S. Pat. No. 9,125,701 and Katz U.S. Pat. No. 7,679,153. As noted inthe details above, it is a clear aspect of a threaded implant to bescrewed in-between the talus and calcaneus bones, so as to bind them ina restored alignment, but in tradeoff for this bound alignment thenatural triplanar motion of the subtalar joint is substantially reducedif not completely eliminated. The stress and force imparted by thisunnatural elimination may and often does cause abrasion of implant andor bone tissue.

The prior art reference of Rappaport U.S. Pat. No. 4,450,591 teaches anInternal Anti-Prorotary Plug Assembly and Process of Installing theSame. Rappaort departs from the threaded implant approach. As taught byRappaport, a biocompatible plastic cone shaped plug is provided with atie line extending from the minor base of the plug. After being insertedinto the sinus tarsus or opening of the subtalar joint, the tie line isbound about the deltoid ligament to hold the cone shaped plug in place.While perhaps avoiding the bound alignment imposed by a threadedimplant, the tie line may cause insult and abrasion to the tendon ascompressive forces upon the conical shaped body result in the generationof lateral forces upon the plug and thereby tension the tie line.Further, the plastic may still abrade or cause the talus and calcaneusbones to abrade.

Moreover, although there are a growing number of implants and procedureswhich strive to alleviate some of the issues associated with flatfoot bystabilizing the subtalar joint, in the main they appear to sacrifice thenatural and expected gliding motion of the joint for improved relativespacing. In addition, as this reduced natural and expected glidingmotion is known to often cause abrasion, extraction and replacement ofthe implants appears to be an expected likelihood in the future,subjecting the patient to an additional surgical procedure as well aspotential pain and discomfort when and if the implant breaks down orabrades body tissues.

Hence there is a need for a system and method that is capable ofovercoming one or more of the above identified challenges.

SUMMARY OF THE INVENTION

Our invention solves the problems of the prior art by providing novelsystems and methods for a non-binding allograft subtalar joint implant.

In particular, and by way of example only, according to one embodimentof the present invention, provided is a method to provide a non-bindingallograft subtalar joint implant into a person's foot proximate to theankle including: surgically accessing a canal within a person's footproximate to the person's talus and calcaneus bones, the canal having awidth between the talus and calcaneus bones; selecting a pre-formedallograft rod plug having a diameter of about the canal width, thepre-formed allograft rod plug being resiliently compressible andflexible; disposing the selected pre-formed allograft rod plug snugglywithin the canal and adjacent to the talus and calcaneus bones, thepre-formed rod plug stabilizing a relative alignment between the talusand calcaneus bones while permitting relative sliding between the talusand calcaneus; evaluating a range of motion of the foot; in response toan abnormal range of motion, removing the pre-formed allograft rod plugand trimming at least a portion of the pre-formed allograft rod plug andredisposing the trimmed pre-formed allograft rod plug within the canalto re-evaluate the range of motion; and in response to a normal range ofmotion, surgically closing access to the canal.

For another embodiment, provided is a method to provide a non-bindingallograft subtalar implant into a person's foot proximate to the ankleincluding: surgically accessing a sinus tarsi within a person's footproximate to the person's talus and calcaneus bones; extracting a fattytissue plug from the sinus tarsi; determining a maximum width within thecanal between the talus and calcaneus bones; selecting a pre-formedallograft rod plug having a diameter of about an equivalent size to thedetermined maximum width, the pre-formed allograft rod plug beingresiliently compressible and flexible; disposing the selected pre-formedallograft rod plug snuggly within the sinus tarsi and adjacent to thetalus and calcaneus bones, the pre-formed rod plug stabilizing arelative alignment between the talus and calcaneus bones whilepermitting relative sliding between the talus and calcaneus bones;evaluating a range of motion of the foot; in response to an abnormalrange of motion, removing the pre-formed allograft rod plug and in afirst instance trimming at least a portion of the pre-formed allograftrod plug and redisposing the trimmed pre-formed allograft rod plugsnuggly within the sinus tarsi to re-evaluate the range of motion, andin a second instance selecting a second pre-formed allograft rod plughaving a different diameter size and disposing the second pre-formedallograft rod plug snuggly within the sinus tarsi to re-evaluate therange of motion; and in response to a normal range of motion, surgicallyclosing access to the sinus tarsi.

Further, in yet another embodiment, provided is a method to provide anon-binding allograft subtalar implant for implant into a person's footproximate to the ankle including: harvesting at least one reticulardermis element from at least one donor; processing the reticular dermiselement to remove cellular component and leave extracellular matrix andscaffold, and drying the reticular dermis element; rolling the processedreticular dermis element into a rod having a diameter about equal to anaverage width of a canal between a person's talus and calcaneus bones,the pre-formed allograft rod plug being resiliently compressible andflexible; cutting the rod into pre-determined lengths; freeze dryingeach cut length; and packaging each freeze dried cut length; whereinwhen unpacked and snuggly disposed between the person's talus andcalcaneus bones, the pre-formed allograft rod plug compresses duringnormal use of the person's foot and maintains the canal in ananatomically correct alignment and reduces a tendency for abnormalmotion between the person's talus and calcaneus bones.

Further still, in yet another embodiment provided is a system to providea non-binding allograft subtalar joint implant into a person's footproximate to the ankle including: at least one sterile pre-formedallograft rod plug having a diameter about equal to an average width ofa canal between a person's talus and calcaneus bones, the pre-formedallograft rod plug being resiliently compressible and flexible; whereinwhen snuggly disposed between the person's talus and calcaneus bones,the pre-formed allograft rod plug compresses during normal use of theperson's foot and maintains the canal in an anatomically correctalignment and reduces a tendency for abnormal motion between theperson's talus and calcaneus bones.

BRIEF DESCRIPTION OF THE DRAWINGS AND SUPPORTING MATERIALS

FIG. 1 illustrates a top view of the bone structure of a human footexhibiting flat foot and a non-binding allograft subtalar joint implantfor reconstructing the foot in accordance with at least one embodimentof the present invention;

FIG. 2 illustrates top view of the bone structure of a human footreconstructed with the a non-binding allograft subtalar joint implant inaccordance with at least one embodiment of the present invention;

FIG. 3 illustrates a side view of the bone structure of the human footshown in FIG. 1 exhibiting flat foot and a non-binding allograftsubtalar joint implant for reconstructing the foot in accordance with atleast one embodiment of the present invention;

FIG. 4 illustrates side view of the bone structure of the reconstructedhuman foot shown in FIG. 2 with the a non-binding allograft subtalarjoint implant in accordance with at least one embodiment of the presentinvention;

FIG. 5 illustrates a side cut through view of the bone structure of thehuman foot shown in FIG. 1 and a plurality of non-binding allograftsubtalar joint implants for reconstructing the foot in accordance withat least one embodiment of the present invention;

FIG. 6 is a high level flow diagram for a method of providing anon-binding allograft subtalar join implant into a person's footproximate to the ankle in accordance with at least one embodiment of thepresent invention;

FIGS. 7A-7C are side cut through views of the bone structure of thehuman foot shown in FIG. 2 and a plurality of non-binding allograftsubtalar joint implants for reconstructing the foot in accordance withat least one embodiment of the present invention;

FIG. 8 illustrates partial top view of the bone structure of a humanfoot reconstructed with the a non-binding allograft subtalar jointimplant shown in FIG. 2 in accordance with at least one embodiment ofthe present invention;

FIG. 9 illustrates partial top bottom of the bone structure of a humanfoot reconstructed with the a non-binding allograft subtalar jointimplant shown in FIG. 2 in accordance with at least one embodiment ofthe present invention;

FIGS. 10A and 10B illustrate a side view and enlarged partial viewsimilar to FIG. 7C, further illustrating the non-binding allograftsubtalar joint implant permitting compression and relative sliding inaccordance with at least one embodiment of the present invention; and

FIG. 11 illustrates the process of making at least one non-bindingallograft subtalar joint implant, such as pre-formed allograft rod plugin accordance with at least one embodiment of the present invention.

DETAILED DESCRIPTION

Our invention solves the problems of the prior art by providing novelsystems and methods for a non-binding allograft subtalar joint implant

Before proceeding with the detailed description, it is to be appreciatedthat the present teaching is by way of example only, not by limitation.The concepts herein are not limited to use or application with aspecific system or method for a non-binding allograft subtalar jointimplant. Thus, although the instrumentalities described herein are forthe convenience of explanation shown and described with respect toexemplary embodiments, it will be understood and appreciated that theprinciples herein may be applied equally in other types of systems andmethods involving or pertaining to a non-binding allograft subtalarjoint implant.

This invention is described with respect to preferred embodiments in thefollowing description with reference to the Figures, in which likenumbers represent the same or similar elements. Further, with therespect to the numbering of the same or similar elements, it will beappreciated that the leading values identify the Figure in which theelement is first identified and described, e.g., element 100 appears inFIG. 1.

Turning now to FIG. 1, presented is a top skeletal view of a person'sfoot 100 exhibiting flatfoot condition before the corrective measure ofimplanting the non-binding allograft subtalar implant 102. An allograftis tissue harvested from one person for surgical transplant to anotherperson. The use of allograft tissue dates back over one hundred andfifty years, and unlike synthetic and metal implants their origin ashuman tissue permits them to be advantageously incorporated by thereceiving body. It should be noted that the Allograft subtalar implant102 is not bone, for a bone implant would likely fuse with the bones ofthe subtalar joint, which for the purposes of reconstruction for normaloperation of the subtalar joint is not necessarily desired.

Rather, for at least one embodiment the allograft subtalar implant 102is formed generally from acellular dermis tissue which has beenprocessed so as to be substantially inert, and while compacted to adensity sufficient to restore about a natural alignment between thetalus 106 and calcaneus 108 bones, it is also resiliently compressible.As such the allograft subtalar implant 102 advantageously provides bothreconstructive support and about natural motion during foot use.

Indeed as the allograft subtalar implant 102 is provided by harvestedhuman tissue that has been processed to an acellular state, it willalmost certainly and advantageously be accepted by the receiving body.More specifically, the inert structure of the allograft subtalar implant102 permitting if not promoting the growth of new tissue which over timewill incorporate it as a part of the receiving body.

As will be further appreciated, for at least one embodiment thenon-binding allograft subtalar implant is a pre-formed allograft rodplug, hereinafter ARP 104. Moreover the ARP 104 has a diameter of aboutthe diameter of a normal canal within a person's foot proximate to thetalus 106 and calcaneus 108 bones.

To briefly summarize, for at least one embodiment provided is anon-binding allograft subtalar joint implant 102 for surgical implantinto a person's foot 100 proximate to the ankle. This system for thisrepair includes at least one sterile ARP 104 having a diameter aboutequal to an average width of a canal between a person's talus 106 andcalcaneus bones 106, the ARP 104 being resiliently compressible andflexible. When snuggly disposed between the person's talus 106 andcalcaneus 108 bones, the ARP 104 compresses and resiliently expands backduring normal use of the person's foot and maintains the canal in ananatomically correct alignment and reduces a tendency for abnormalmotion between the person's talus 106 and calcaneus 108 bones.

Advantageously, and as will be further appreciated with the followingdescription, the ARP 104 is non-binding to the talus 106 and calcaneus108 bones, being held in place by the resilient nature of the ARP 104.Indeed this lack of anchoring by threads or grooves caused to bite intothe talus 106 and calcaneus 108 bones permits the ARP 104 to stabilizethe relative alignment between the talus 106 and calcaneus 108 boneswhile permitting relative sliding between the talus 106 and calcaneus108. Indeed, as used herein, the term “snuggly” as used to describe thefit of ARP 104 within the canal, is understood and appreciated to conveythe understanding that it is a tight but comfortable fit, permittingsome movement without anchoring or binding the talus 106 and calcaneus108 in a substantially ridged alignment.

To facilitate the description of systems and methods for thisnon-binding allograft subtalar joint implant, or ARP 104, theorientation of the foot and ARP 104 as presented in the figures arereferenced to the coordinate system with three axis orthogonal to oneanother as shown in FIG. 1. The axis intersect mutually at the origin ofthe coordinate system, which is chosen to be the center of the person'sfoot, however the axes shown in all figures are offset from their actuallocations for clarity and ease of illustration.

In a normal healthy foot, a longitudinal midline may be viewed runningthrough at least the second metatarsal 110, the talus 106 and thecalcaneus 108. However in the flatfoot conceptualized by FIG. 1, thislongitudinal midline is distorted, as shown by dotted line 112. Indeed,as shown in FIG. 1 the head of the talus 106 is disposed away from thesecond metatarsal 110 so as to even protrude along the inside edge ofthe person's foot.

Moreover, for the flatfoot condition, the misalignment of the bones inthe subtalar joint, and most specifically the talus 106 and calcaneus108, results in a significant displacement of the bones and frustratesthe longitudinal axis 112. The canal within the foot 100 defined by thetalus 106 and calcaneus 108 is impinged as well, such that for FIG. 1,it is shown merely as a dotted line 114. This canal 114 or cylindricalcavity as it may also be described is often referred to as the sinustarsi.

The flatfoot condition can be repaired. As shown in FIG. 2, with the ARP104 snuggly disposed within the canal 114 such that the canal 114 isspread back substantially to about a normal width, the alignment of thetalus 106 and calcaneus 108 is vastly corrected to approach, if notreestablish, a normal alignment, providing repaired foot 200. Incontrast to FIG. 1, in FIG. 2 the longitudinal axis 202 through thesecond metatarsal 110, the talus 106 and calcaneus 108 is now normal,for repaired foot 200.

FIG. 3 is a side view corresponding to FIG. 1 of foot 100 in the initialflatfoot condition. As with FIG. 1 the alignment of the bones isdistorted and the arch 300 of the foot 100 is substantiallynon-existent. In addition, the talus 106 and calcaneus 108 are somisaligned that the canal 114 between them is not even radiallyapparent, shown merely as a conceptual dot 302. FIG. 3 also illustratesthe line-of-sight view “5” for FIG. 5 below conceptualizing across-section view proximate to the canal 114 of foot 100 before repair.

FIG. 4 is a side view of repaired foot 200 shown in FIG. 2. As shown,ARP 104 is snuggly disposed within the canal 114. A visual comparisonwith FIG. 3 helps further demonstrate how reestablishing the canal 114,by lifting the talus 106 away from the calcaneus 108 effectively liftsthe entire bone structure of the repaired foot 200. Indeed raising thehead of the talus 106 acts as a lever arm and pulls upon the tendons ofthe foot to naturally realign a plurality of bone elements withinrepaired foot 200.

As shown, repaired foot 200 has a substantially normal arch 400. As withFIG. 3, FIG. 4 also illustrates the line-of-sight views “7”, “8” and “9”for FIGS. 7, 8 and 9 respectively.

FIG. 5 as noted above is a cross-section view of foot 100 before repair.In this view, the misalignment of the talus 106 and the calcaneus 108 ismore fully appreciated. Indeed the canal 114, and more specifically theregion within dotted oval 500 is substantially compressed together. Inaddition, the relative improper angles of the head 502 of the talus 106and the head 504 of the calcaneus 108 are shown with side view surfaceangle representations 502A and 504A respectively.

Also shown in FIG. 5 are ARP 104A having a length that is longer thanthe average sinus tarsi and a diameter of about the average width of anormal sinus tarsi, ARP 104B having a length that is longer than theaverage sinus tarsi and a diameter smaller then the average width of anormal sinus tarsi, and ARP 104C having a length that is longer than theaverage sinus tarsi and a diameter larger then the average width of anormal sinus tarsi. Moreover, a selection of different ARP 104 implantseases the ability of the surgeon performing the repair to select an ARP104 which will most closely approximate the width of the sinus tarsi inthe person's foot being reconstructed.

More specifically, for at least one embodiment, ARP 104A has a length ofabout 25 mm and a diameter of about 10 mm, ARP 104B has a length ofabout 25 MM and a diameter of about 8 mm, and ARP 104C has a length ofabout 25 mm and a diameter of about 12 mm. Of course in varyingembodiments ARP 104 implants having alternative diameters, and/or evendifferent lengths, may be provided.

As has also been shown by way of illustration, in initial state, eachARP 104 implant has a generally consistent diameter. It should also beunderstood and appreciated that each ARP 104 implant is also resilientlycompressible and flexible. Moreover, as will be further discussed below,each ARP 104 is not a ridged element and is not constructed withanchoring elements such as screw threading, channeling or tether.

Indeed as each ARP 104 is slightly compressible, it is the resilientnature of the ARP 104 that permits it to be disposed within the sinustarsi 114 adjacent to the talus 106 and calcaneus 108 so as to maintainthe sinus tarsi 114 in about a normal open state and stabilize therelative alignment between the talus 106 and calcaneus 108 whilepermitting relative sliding between the talus 106 and calcaneus 108.Moreover, the resilient nature of the ARP 104 permits it toadvantageously remain in a snug position within the canal 114 whileadvantageously also permitting natural movement of the talus 106 andcalcaneus 108 that is not otherwise achieved with a more traditionalanchoring implant that is screwed, bound or otherwise affixed in placeby a surgeon or other repairing technician.

For at least one embodiment, the method of providing a non-bindingallograft subtalar implant into a person's foot proximate to the anklemay be summarized as follows. Surgically accessing a canal 114 within aperson's foot proximate to the person's talus 106 and calcaneus 108bones and determining a maximum width within the canal between the talus106 and calcaneus 108 bones. With the maximum width determined,selecting an ARP 104 having a diameter of about an equivalent size tothe determined maximum width, the pre ARP 104 being resilientlycompressible and flexible. The selected ARP 104 is then snuggly disposedwithin the canal and adjacent to the talus 106 and calcaneus 108 bones,the ARP 104 stabilizing a relative alignment between the talus 106 andcalcaneus 108 bones while permitting relative sliding between the talus106 and calcaneus 108. The range of motion of the foot is thenevaluated. In response to an abnormal range of motion the disposed ARP104 is removed. In a first instance, a portion is trimmed and thetrimmed ARP 104 is redisposing snuggly within the canal 114 tore-evaluate the range of motion. In a second instance a second ARP 104is selected having a different diameter size. This second ARP 104 isthen snuggly disposed within the canal to re-evaluate the range ofmotion. In response to a normal range of motion, surgically closingaccess to the canal.

Methods of repair are perhaps more fully appreciated with respect to anexemplary method 600 shown in FIG. 6 in connection with at least FIGS.7A and 7B. It is also to be understood and appreciated the describedmethod need not be performed in the order in which it is hereindescribed but that this description is merely exemplary of at least onemethod for advantageously providing a non-binding allograft subtalarimplant into a person's foot proximate to the ankle.

In general, as shown in FIG. 6, method 600 commences by surgicallyaccessing the canal 114 proximate to the talus 106 and calcaneus 108bones, block 602. It is very common for a fatty tissue plug to benaturally occurring within the canal 114, which may optionally beremoved, optional block 604.

With the canal 114 now exposed, it is appropriate to select an ARP 104with a diameter about equal to the width of the canal, block 606. For atleast one embodiment, the surgeon may start by selecting an ARP 104having a diameter that is about equivalent to the average width of thecanal 114 in an average person.

An improved selection of an ARP 104 may be facilitated by determiningthe maximum width of the canal 114 for the current patient, block 608.For at least one embodiment, this determination of maximum width isoptionally achieved through the use of sizers/spacers which correlate insize to various ARP 104 implant options.

More specifically, as was discussed above with respect to FIG. 5, thecanal in the flatfooted patient is likely substantially collapsed.Accordingly, the surgeon or other operating assistant may articulate theperson's foot so as to open the canal 114, optional block 610.

In FIG. 7A the foot 100 has been manipulated, as indicated by arrows700, so as to realign the talus 106 and calcaneus 108 in about a normalorientation. This manipulation serves to also open the canal regionshown within dotted circle 702, and more specifically the sinus tarsi114. The dotted side line 702 in FIG. 7A represents the originalposition of the talus 106 as shown in FIG. 5. In addition, the sinustarsi 114 is shown now open and having a maximum width W.

As shown in FIG. 7B, this width W of the sinus tarsi 114 may be measuredthrough the use of one or more spacer 706, such as spacers 706A, 706Band 706C which correlate in diameter to the implants ARP 104A, ARP 104Band ARP 104C. For at least one embodiment, each spacer 706 is a blunttrocar which may be introduced to the sinus tarsi 114 along a Kircshnerwire 708, such as a 0.062 inch Kircshner wire serving as a guide wire.More specifically, for at least one embodiment, each spacer 706 isintroduced to the sinus tarsi 114 through a cannula (not shown) andpushed into place with a trocar. Following the spacing evaluation thespacer 706 is extracted. The Kircshner wire serves as an additionalguide for this process. Of course in varying embodiments, the surgeonmay use other instrumentation to position and remove each spacer 706.

Moreover, with respect to FIG. 7B, spacer 706A is selected, optionalblock 612, and disposed to the canal 114 along a Kircshner wire,optional block 708. The surgeon then evaluates the fit of the spacer,optional decision 616. If it is too big or too small, the surgeon thenselects an alternative spacer, optional block 612 and repeats theprocess. When the fit is as desired, optional decision 616, the width Wof the sinus tarsi canal 114 is known to be the diameter of the currentspacer 706, optional block 618. With this determined width W, thesurgeon then selects an ARP 104 with a diameter about equivalent to thespace, block 606.

Having selected an ARP 104 of an appropriate size, if the foot is notproperly articulated to open the canal, the surgeon now does so, block620. Method 600 proceeds with the ARP 104 being snuggly disposed withinthe sinus tarsi 114 as shown in FIG. 7C. More specifically, the ARP 104is disposed snuggly within the narrow region of the sinus tarsi canal114 such that the ARP 104 is in compressive contact with both the tarsi106 and calcaneus 108. Indeed the ARP 104 may be disposed in directcontact with actual bone tissue of the tarsi 106 and calcaneus 108, orin direct contact with one or more tissues covering the bone tissue ofthe tarsi 106 and calcaneus 108. For at least one embodiment, the ARP104 is pre-trimmed prior to being snuggly disposed within the sinustarsi 114. As with the placement of one or more spacers 706, a cannula(not shown) and trocar may be used to position and snuggly dispose ARP104 within the sinus tarsi canal 114.

With the ARP 104 now disposed, the range of motion of the foot 100 sevaluated, block 622. This range of motion of the foot 100, and morespecifically the subtalar joint is performed by rotating the foot 100from side to side about the X-Axis as shown in FIG. 7B by arrows 710. Ina normal foot, this range of side to side motion is typically no morethan 4 degree to either side of normal, and more preferably no more than2 degrees to either side of normal. More specifically, for at least oneembodiment an evaluation of rotation motion is performed to confirm nomore than 2 degrees of inverted rotation and no more than 2 degrees ofeverted rotation. Accordingly, for at least one embodiment, the surgeonarticulates the calcaneus 108 and checks for more than 2 degrees ofmotion from side to side.

If the disposed ARP 104 does not permit the proper range—either too muchor too little, decision 626, the disposed ARP 104 is removed from thecanal 114, block 628. For at least one embodiment, method 600 proceedswith an evaluation of whether to trip the ARP 104 or select another ARP104 having a different diameter, decision 630.

In a first instance, the decision is to trim the ARP 104, block 632 andthen snuggly dispose the trimmed ARP 104 within the canal 114, block622. In a second instance, the decision is to select a second ARP 104having a different diameter size, block 634 and then dispose the secondARP 104 within the canal 114, block 622. Following the trimming orselection of a replacement ARP 104, the evaluation of motion isperformed once again, block 624, and the process of trimming orreselecting repeated if necessary.

When the range of motion is in the desired range, decision 626, thealignment of the tarsi 106 and calcaneus 108 is understood to becorrected. Now, the relative proper angles of the head 502 of the talus106 and the head 504 of the calcaneus 108 for repaired foot 200 areshown with side view surface angle representations 502A′ and 504A′respectively.

The surgeon then proceeds to surgically close access to the canal 114,block 636. Of course, in this closing process, the surgeon may alsooptionally trim the excess 712 of ARP 104 which may extend from thecanal 114, optional block 638.

FIG. 8 presents the ARP 104 snuggly disposed within the sinus tarsi 114as viewed from above, generally along the line of sight 8 as suggestedin FIG. 4, i.e. a top view. Shown are features of the calcaneus 108 thatdefine the bottom half of the sinus tarsi 112. In this view, the sinustarsi 114 is posterior to (as in behind) the middle 800 and anteriortalar facet 802 of the calcaneus 108. The sinus tarsi 114 is anterior to(as in front of) the subtalar joint provided in part by the posteriortalar facet 804 of the calcaneus 104.

FIG. 9 presents the ARP 104 snuggly disposed within the sinus tarsi 114as viewed from below, generally along the line of sight 9 as suggestedin FIG. 4, i.e., a bottom view. Shown are the features of the talus 106that define the top half of the sinus tarsi 114 in complement to thosefeatures shown in FIG. 9. Specifically, the sinus tarsi 114 is shownposterior to (as in behind) the talocalcaneonavicular joint whichcomprises the middle 900 and anterior calcaneal facet of the talus 106.The sinus tarsi 114 is anterior to (as in front of) the subtalar jointprovided in part by the posterior calcaneal facet 902 of the talus 106.

Moreover, as shown in FIG. 10A, presenting substantially the same viewas FIG. 7C of repaired foot 200, snuggly disposed, ARP 104 now maintainsthe sinus tarsi 114 in an anatomically correct alignment and reduces atendency for abnormal motion between the person's talus 106 andcalcaneus 108. In addition, as shown in the enlarged section of FIG.10B, the ARP 104 advantageously compresses (shown by force arrows 1002)the during normal use of the person's repaired foot 200, shown by dottedlines 1000 indicating the original uncompressed sidewall of ARP 104.Further still, ARP 104 can advantageously distort laterally as well inresponse to relative sliding motions, shown by arrow sliding arrows1004, during the normal use of the person's repaired foot 200, shown bydotted lines 1006 indicating potential end distortion as the talus 106and calcaneus 108 move relative to each other.

Moreover, ARP 104 provides the anatomical lifting of the talus 106relative to the calcaneus 108 as other implants strive to achieve, butthe ARP 104 is advantageously distinct in not being anchored byartificial means such as threads, grooves or ties. The ARP 104 thereforepermits partial compression from loading 1002 during use of the footwhile still achieving the leverage based realignment of the talus 102and relative sliding 1004 and/or gliding between the talus 106 andcalcaneus 108 as is found in a healthy foot.

The advantages of the ARP 104 are achieved by the nature of the ARP 104.Specifically, for at least one embodiment ARP 104 is provided by a rodof acellular dermis. Dermis is a layer of skin between the epidermis andsubcutaneous tissues. The dermis is divided into two layers, thesuperficial area adjacent to the epidermis called the papillary regionand a deep thicker area known as reticular dermis. Structural componentsof the dermis are collagen, elastic fibers and extrafibrillar matrix.

Constructed as a rod, and more specifically a rolled rod, ARP 104provides excellent compressive resistance and is thereby capable ofreestablishing the sinus tarsi 114 to about a normal width W, yet stillpermits some resilience permitting normal relative motion between thetalus 106 and the calcaneus 108 during normal use of the repaired foot200.

To provide ARP 104, for at least one embodiment, skin may be harvestedfrom a healthy donor, who has been screened for a plurality of viral,bacterial, and fungal diseases and aliments. In addition, it is expectedthat the donor will have a healthy past medical and social history asper AATB standards. Skin tissue of this type is generally removed by,and available from, accredited US Tissue Banks which operate understrict aseptic conditions.

If not previously processed, the dermis may be separated from theepidermis using a skin splitter, such as but not limited to the AesculapAcculan 3Ti Dermatome which permits adjusted thickness from 0.2 to 1.2mm in lockable 1/10 mm increments. This recovered dermis is thenprocessed to remove the cellular components and leave the extracellularmatrix and scaffold. This resulting extracellular matrix and scaffoldwill then be dried. For at least one embodiment, this drying isperformed using traditional lyophilizing techniques, leavingapproximately 10-15% moisture residue in the tissue.

As shown in FIG. 11, a reticular dermis element 1100 that has beenprocessed as described above is shown. For at least one alternativeembodiment, a plurality of dermis elements 1100 may be stacked, as shownin stack 1102.

Either as a single sheet, or stack 1102, the processed dermis 1100 isthen tightly rolled into rods 1104 having desired diameters.Corresponding to the above discussion, it will be understood andappreciated that a resulting rod has a diameter about equal to theaverage width W of the sinus tarsi 114. Additional rods having diameterslarger then the average width of the sinus tarsi 114 and smaller thanthe average width of the sinus tarsis 114 are also provided inaccordance with at least one embodiment.

Each rod is then cut to provide the allograft rod plugs, i.e. ARP 104.For at least one embodiment the length of the each ARP 104 is about 25mm. Each ARP 104 is then individually packaged. For at least oneembodiment these individual packages are DuPont™ Tyvek® pouches made ofhigh-density polyethylene which is extremely stable when exposed tosterility gases and high-energy sterilization processes.

Once packaged, the ARP 104 implants will undergo a second drying. Onceagain, for at least one embodiment this second drying process is aperformed using traditional lyophilizing techniques for freeze drying,leaving approximately about 4% to 6% residual moisture within each ARP104. This freeze drying per AAATB standards is sufficient to maintainthe rod shape and preserve each ARP 104 for long term storage.

Moreover, for at least one embodiment a plurality of ARPs 104 along withcorresponding spacers 706, and a Kirschner wire to act as guide may bepre-packaged as a repair non-binding allograft subtalar joint implantkit.

Of course it should be understood and appreciated that the abovemethods, system and structures may be adapted and applied to othersimilar reconstructions of other joints and/or body appendages, such asfor example the human hand.

Changes may be made in the above methods, systems and structures withoutdeparting from the scope hereof. It should thus be noted that the mattercontained in the above description and/or shown in the accompanyingdrawings should be interpreted as illustrative and not in a limitingsense. Indeed many other embodiments are feasible and possible, as willbe evident to one of ordinary skill in the art. The claims that followare not limited by or to the embodiments discussed herein, but arelimited solely by their terms and the Doctrine of Equivalents.

What is claimed is:
 1. A system to provide a non-binding allograftsubtalar joint implant into a person's foot proximate to the ankle,comprising: at least one sterile pre-formed allograft rod plug having adiameter about equal to an average width of a canal between a person'stalus and calcaneus bones and a density sufficient to resist fullcompression of the canal, the pre-formed allograft rod plug beingresiliently compressible and flexible while remaining substantially asthe formed plug, the allograft; wherein when snuggly disposed betweenthe person's talus and calcaneus bones, the pre-formed allograft rodplug compresses and expands back to about the diameter of the canalduring normal use of the person's foot and maintains the canal in ananatomically correct alignment and reduces a tendency for abnormalmotion between the person's talus and calcaneus bones.
 2. The system ofclaim 1, wherein the pre-formed allograft rod plug is non-binding to thetalus and calcaneus bones.
 3. The system of claim 1, wherein thepre-formed allograft rod plug stabilizes a relative alignment betweenthe talus and calcaneus bones while permitting relative sliding betweenthe talus and calcaneus bones.
 4. The system of claim 1, wherein thepre-formed allograft rod plug is generally acellular dermis.
 5. Thesystem of claim 1, wherein the canal is a sinus tarsi.
 6. The system ofclaim 1, wherein the canal is an opening of a subtalar joint of theperson's foot.
 7. The system of claim 1, wherein the system includes atleast one second pre-formed allograft rod plug with a diameter smallerthan the average width of the canal between a person's talus andcalcaneus bones and at least one third pre-formed allograft rod plugwith a diameter larger than the average width of the canal between aperson's talus and calcaneus bones.
 8. The system of claim 1, wherein afirst pre-formed allograft rod plug is provided with a length of about25 mm and a diameter of about 8 mm, a second pre-formed allograft rodplug is provided with a length of about 25 mm and a diameter of about 10mm, and a third pre-formed allograft rod plug is provided with a lengthof about 25 mm and a diameter of about 12 mm.
 9. The system of claim 1,wherein each pre-formed allograft rod plug is provided by: harvesting atleast one reticular dermis element from at least one donor; processingthe reticular dermis element to remove cellular component and leaveextracellular matrix and scaffold, and drying the reticular dermiselement; rolling the processed reticular dermis element into a rod;cutting the rod into pre-determined lengths; freeze drying each cutlength; and packaging each freeze dried cut length.
 10. The system ofclaim 9, wherein each reticular dermis element is between about 1-3 mmthick and has about 4 to 12 cubic centimeters of dermis.
 11. The systemof claim 9, wherein the freeze drying results in less than 4-6% residualmoisture within each cut length.
 12. The system of claim 1, wherein thesystem is suitable for storage at room temperature for a period of atleast two years.
 13. The system of claim 1, wherein the plug cannot beunrolled.
 14. The system of claim 1, wherein the plug cannot beunfolded.
 15. The system of claim 1, wherein the plug has a density suchthat it may be compressed by about ¼ its diameter.
 16. The system ofclaim 1, wherein the plug has a density such that it may be compressedby about ⅛ its diameter.
 17. A system to provide a non-binding allograftsubtalar joint implant into a person's foot proximate to the ankle,comprising: at least one sterile pre-formed allograft rod plug having adiameter about equal to an average width of a canal between a person'stalus and calcaneus bones, the pre-formed allograft rod plug beingresiliently compressible and flexible while remaining substantially asthe formed plug, the pre-formed allograft rod plug having a density suchthat it is resistant to compression beyond about ⅔ of its diameter;wherein when snuggly disposed between the person's talus and calcaneusbones, the pre-formed allograft rod plug compresses and expands back toabout the diameter of the canal during normal use of the person's footand maintains the canal in an anatomically correct alignment and reducesa tendency for abnormal motion between the person's talus and calcaneusbones.
 18. The system of claim 17, wherein the pre-formed allograft rodplug is non-binding to the talus and calcaneus bones.
 19. The system ofclaim 17, wherein the pre-formed allograft rod plug stabilizes arelative alignment between the talus and calcaneus bones whilepermitting relative sliding between the talus and calcaneus bones. 20.The system of claim 17, wherein the pre-formed allograft rod plug isgenerally acellular dermis.
 21. The system of claim 17, wherein thecanal is a sinus tarsi.
 22. The system of claim 17, wherein the canal isan opening of a subtalar joint of the person's foot.
 23. The system ofclaim 17, wherein the system includes at least one second pre-formedallograft rod plug with a diameter smaller than the average width of thecanal between a person's talus and calcaneus bones and at least onethird pre-formed allograft rod plug with a diameter larger than theaverage width of the canal between a person's talus and calcaneus bones.24. The system of claim 17, wherein a first pre-formed allograft rodplug is provided with a length of about 25 mm and a diameter of about 8mm, a second pre-formed allograft rod plug is provided with a length ofabout 25 mm and a diameter of about 10 mm, and a third pre-formedallograft rod plug is provided with a length of about 25 mm and adiameter of about 12 mm.
 25. The system of claim 17, wherein eachpre-formed allograft rod plug is provided by: harvesting at least onereticular dermis element from at least one donor; processing thereticular dermis element to remove cellular component and leaveextracellular matrix and scaffold, and drying the reticular dermiselement; rolling the processed reticular dermis element into a rod;cutting the rod into pre-determined lengths; freeze drying each cutlength; and packaging each freeze dried cut length.
 26. The system ofclaim 17, wherein each reticular dermis element is between about 1-3 mmthick and has about 4 to 12 cubic centimeters of dermis.
 27. The systemof claim 17, wherein the plug cannot be unrolled.
 28. The system ofclaim 17, herein the plug cannot be unfolded.